Vacuum Pump Questions

[Christopher K. Hartley]

I was in a local Pawn shop today and ran accross three vacuum pumps on the shelf. Two of them caught my eye because they looked exactly like the Gast Pumps often recommended for our usage. The two are GE Pumps, G213DX and are available for $99.00 each. The third is a Deep Vacuum 2 Stage "Fast Vac DV85" 3CFM it lists at $159.00. Knowing nothing about these things, I was wondering if this might be a find or not worth the effort.:) I couldn't find them on the internet. Just found this link on Ebay that looks just like the third pump. The Ebay one looks better,

[Kurt Rosenzweig]

PM sent Chris!:D

[Carroll Courtney]

I like the fast vac.We use them at work for pulling a vaccum on A/C epuipment.Sometimes we let them run all night,they do get warm but that's it.Look at the oil in the pump and make sure it does not smell burn't.I also use one at home that I use on my vaccum bag.Just keep the oil change and it will last a life time.Their alittle over 300.00 new,I would offer them 100.00 and go from there.Good Luck Carroll

[Bill Boehme]

I was in a local Pawn shop today and ran accross three vacuum pumps on the shelf. Two of them caught my eye because they looked exactly like the Gast Pumps often recommended for our usage. The two are GE Pumps, G213DX and are available for $99.00 each. The third is a Deep Vacuum 2 Stage "Fast Vac DV85" 3CFM it lists at $159.00.
If you check more closely, you will probably find that the first two are indeed Gast pumps -- you saw the GE label on them because Gast uses GE motors a lot on their vacuum pumps. They also use a lot of Emerson motors.

Ideally what you want is a non-lubricated rotary vane pump because they have a high flow rate while maintaining a fairly constant level of vacuum. You should aim for a non-lubricated rotary vane pump with a open-port flow rate of 4.5 CFM and a blocked-port vacuum of 26 inches of Mercury. Some of the other types of pumps can have large amplitude pressure pulses especially the piston type. The piston type pumps do produce very high vacuum, but unless it is a very large unit, the flow rate may not be great and you will need a tank to filter out the ripple in pressure. There is also an oil-lubricated rotary vane pump, but it is less desirable than the dry vane type because of the messiness of the oil and the possibility of dust mixing with the oil and requiring more frequent maintenance. The are also diaphram vacuum pumps at the low end of the spectrum, but they are not very satisfactory for vacuum chucking because their flow rate is very low and they are not able to pull as much vacuum as the other types if there is any leakage flow at all -- and there will be.

Bill

[Christopher K. Hartley]

Bill, thanks this really helps to know what to look for. :) When looking at a used pump is there anyway to be certian if it is in good condition?

[Bill Boehme]

Bill, thanks this really helps to know what to look for. :) When looking at a used pump is there anyway to be certian if it is in good condition?

Carry a gauge with you and insist that they run it. An honest person would not have any problem in complying with this request.

If it looks like it has been through two world wars then it is probably junk. One that appears to be in pristine condition with no rust, chips, scratches, and dents has a better chance of being good than one that looks like heck, but you can never be absolutely certain by merely looking.

If you buy one on ebay check the seller's feedback record first. I normally don't even bother looking if the feedback record is less than 99.5%. Next, I read what the buyers say about their dealings with the seller. Very frequently, a good deal on a Gast pump pops up on ebay.

Bill

Bill

[Joe Melton]

Personally, I would not buy something like this in a pawn shop. The owner will not know a thing about the condition, and will almost certainly not stand behind it if there is a problem.
I bought a 110V pump on ebay, and it is fine. I think I paid 70 dollars. This one is used in stabilization. I also bought one of the 89.95 Gast pumps at surpluscenter.com, part number 4-1540, and it was brand new. It is 220V, though. I mounted it upside down on the ceiling so as to save floor space, and have it connected to my lathe. Surpluscenter also sells gages and filters for very low prices.
Joe

[Stephen Mushinski]

I mounted it upside down on the ceiling so as to save floor space, and have it connected to my lathe. Surpluscenter also sells gages and filters for very low prices.
Joe

I sure like this idea Joe. Thanks I am going to try the same thing!

[Christopher K. Hartley]

Thanks everyone!:)